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authorEric Biggers <ebiggers@google.com>2018-01-19 15:15:34 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-17 13:21:14 +0100
commit967f650f8835012e9d8bf96bdace29a6b84b43db (patch)
tree9659ed1e0af2f4062f5de36553063332e8cdb2e4 /fs
parentca2c316f7cb490c350b101d59c1b892970ac33d0 (diff)
NFS: reject request for id_legacy key without auxdata
commit 49686cbbb3ebafe42e63868222f269d8053ead00 upstream. nfs_idmap_legacy_upcall() is supposed to be called with 'aux' pointing to a 'struct idmap', via the call to request_key_with_auxdata() in nfs_idmap_request_key(). However it can also be reached via the request_key() system call in which case 'aux' will be NULL, causing a NULL pointer dereference in nfs_idmap_prepare_pipe_upcall(), assuming that the key description is valid enough to get that far. Fix this by making nfs_idmap_legacy_upcall() negate the key if no auxdata is provided. As usual, this bug was found by syzkaller. A simple reproducer using the command-line keyctl program is: keyctl request2 id_legacy uid:0 '' @s Fixes: 57e62324e469 ("NFS: Store the legacy idmapper result in the keyring") Reported-by: syzbot+5dfdbcf7b3eb5912abbb@syzkaller.appspotmail.com Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Trond Myklebust <trondmy@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/nfs/nfs4idmap.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/nfs/nfs4idmap.c b/fs/nfs/nfs4idmap.c
index c444285bb1b1..f1160cdd4682 100644
--- a/fs/nfs/nfs4idmap.c
+++ b/fs/nfs/nfs4idmap.c
@@ -567,9 +567,13 @@ static int nfs_idmap_legacy_upcall(struct key_construction *cons,
struct idmap_msg *im;
struct idmap *idmap = (struct idmap *)aux;
struct key *key = cons->key;
- int ret = -ENOMEM;
+ int ret = -ENOKEY;
+
+ if (!aux)
+ goto out1;
/* msg and im are freed in idmap_pipe_destroy_msg */
+ ret = -ENOMEM;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
goto out1;